The invention relates to reactive polyurethane which has the content of low monomer diisocyanate, the preparation thereof, and the application thereof in reactive mono-component and bi-component binding agent/sealant, assembling foam, compound for casting, and soft and hard and integral foam. The polyurethane is prepared under the condition of acetylacetone zirconium (IV) complex compound adoptedas catalytic agent, wherein at least one acetylacetone ide ligand in the catalytic agent is provided with fluorine substituent.